The present invention relates generally to electronic keyboard musical instruments and, in particular, to an electronic organ in which the data representing one or more depressed keys can be latched for continuously producing corresponding output tones until at least one new key is depressed thereby freeing the hands of the player for operating other portions of the organ.
A keyboard musical instrument such as an electronic organ typically includes an upper or solo keyboard manual, a lower or accompaniment keyboard manual, a tone generator, and a plurality of keyers coupling the tone generator to a voicing circuit which, in turn, is connected through an amplifier to a speaker. The keyers are operable in response to depressed keys on the keyboard manuals for supplying appropriate tone signals from the tone generator to the voicing circuit and amplifier for sounding through the speaker. In addition, modern day electronic organs frequently utilize a time multiplexing mode of operation wherein the keys of one or both of the keyboard manuals are repetitively scanned for developing time encoded serial data streams identifying the depressed keys of the respective keyboards. A demultiplexer subsequently decodes the data streams for enabling actuation of the appropriate keyers.
The lower keyboard manual of the organ is typically operated by the player for sounding a selected chord to accompany the melody played on the upper manual. In order to continuously sound a desired accompaniment chord on the lower keyboard manual, the player must normally maintain the appropriate keys depressed with his left hand for repetitively supplying the corresponding serial data stream to the demultiplexer and keyers. In the meantime, the player's right hand may be utilized to play the melody on the upper manual and to otherwise operate the organ, for instance, to change the registration thereof. Although the foregoing organ playing technique is normally considered acceptable, it is desirable in certain instances to free the player's left hand to assist his right hand while still sounding a desired accompaniment chord. For example, U.S. Pat. No. 4,147,085 to Robinson et al discloses an electronic organ having a control circuit actuated by a knee operated switch for preventing the data supplied to the demultiplexers from being updated at the end of each keyboard scan whereby the data consequently held in the demultiplexer is effective for causing corresponding tone signals to be sounded even though the associated keys are not depressed. This approach suffers from the attending inconvenience of coordinating the operation of the knee switch with the operation of the keyboard keys.
It is a primary object of the present invention to provide an electronic organ including means responsive only to the operation of the keys of a keyboard manual for enabling selected groups of one or more tone signals to be successively sounded for desired time intervals even though the associated keys are not continuously depressed thereby freeing a hand of the player for operating other portions of the organ.